As a problem common to zinc-alkaline batteries, there is raised the corrosion of the anode zinc caused by the electrolyte. Namely, zinc is so reactive in an alakli electrolyte as reacting with the electrolyte during long term storage, thereby undergoing self-corrosion in accordance with the following equation: EQU Zn+4OH.sup.- .fwdarw.Zn(OH.sub.4.sup.2- +2e.sup.- EQU 2H.sub.2 O+2e.sup.- .fwdarw.2OH.sup.- +H.sub.2 .uparw.
Hydrogen gas generated from the corrosion causes gas pressure in the battery to elevate, which involves the danger of causing leakage of electrolyte, bursting and the like. Accordingly, it has been hitherto adopted as an industrial technique to use amalgamated zinc powder which was prepared by adding about 5 to 10% by weight of mercury to zinc, to increase thus the hydrogen overvoltage and to suppress the corrosion to a practically allowable level. In recent years, however, it has been a increasing social demand to decrease the amount of mercury contained in a battery for lowering environmental pollution, and various studies have been conducted. For example, methods have been proposed which use zinc alloy powder formed by adding Pb, Ga, In etc. having high hdyrogen overvoltage into zinc to improve corrosion resistance and to decrease mercury concentration rate. These methods are effective to some extent in corrosion inhibition and give a zinc anode of nearly satisfactory corrosion resistance until a mercury concentration rate of about 3% by weight. However, when the mercury concentration rate is further decreased, zinc anodes obtained by these methods do not have sufficient corrosion resistance, and hydrogen gas generated during storage is accumulated on the surface or in the neighborhood of the anode active material, which causes the deterioration of discharge performance and can sometimes cause the expansion of the battery or the leakage of electrolyte, and thus they have a defect of insufficient storage property.
Further, it has been proposed, mainly with the view of improving manganese dry batteries, that a good corrosion inhibitory effect can be obtained by using for an anode a zinc alloy formed by adding In to zinc or zinc alloy [Japanese Patent application Kokoku (PostExam. Publn.) No. 3204/58]. The description of the above proposal includes cases wherein, besides In, one or more elements selected from Pb, Cd, Al, Mg, iron, chromium, calcium, mercury, bismuth, antimony, silver, silicon, nickel manganese etc. are added to zinc as an impurity or as an additive. However, it does not state clearly whether the above-mentioned various elements are each contained as in impurity or added as an effective additive except for the effectiveness of In and Pb used in combination as additive elements. Further, it neither states which element is effective for corrosion inhibition, nor shows the suitable amount to be added except those for In and Pb. Thus, no investigation has ever been made on the effect of combined use of these elements, particularly for zinc-alkaline battery, to find an effective zinc alloy composition.